Dental work on teeth and other parts of the oral cavity has to be very accurately and delicately performed. It is essential that the dental surgeon, since he works in an otherwise dark cavity, has available to him a strong light beam which he can direct onto the spot which he is drilling or grinding and that such light should be of a kind which is not obstructed by the dentist's hands or head.
Existing equipment used by dentists to direct light rays from an external light source into the mouth of the patient conventionally requires the use of a small mirror. This is quite inconvenient since it occupies both of the dentist's hands, one hand holding the drill and the other hand holding the mirror. Furthermore, there is in the use of this method the danger of the obstruction of the light path by the dentist's hands or body.
In an effort to overcome the aforesaid problems a form of direct illumination was introduced a few years ago using optical fibers for transferring a light beam from an external source to a point just above the burr in the dental handpiece. In the known apparatus the light source is generally on the main frame of the drilling apparatus and has its beam directed into the receiving end of a flexible fiber-optic bundle. This flexible fiber-optic bundle extends from the stationary light source to the connector to which the handpiece is connected. A second fiber-optic bundle then extends through the handpiece to a point above the burr for directing the light beam toward the point of the burr. The connector required for connecting the removable handpiece, with its optical fibers, to the remainder of the drill apparatus must, of course, be of special construction since the optical fibers of the two bundles must be connected to one another in such a manner as to permit the passage of light through the connection thus formed. It has been found that this type of apparatus suffers from a number of disadvantages: First is the high cost of known fiber-optic devices. Second, the continuous flexing of the first fiber-optic bundle in response to movement of the handpiece results in elastic deformation along the length of the fibers, which in turn may result in fluctuations in the light intensity of the beam at the very time when drilling is taking place. Furthermore, use of fiber optics requires standardization of equipment since only handpieces equipped with the aforesaid special connector can be used in the installation with drill apparati which themselves must contain a light source and the aforesaid fiber optic capability.
It is therefore an object of the present invention to provide a dental handpiece which will overcome the disadvantages mentioned above.
It is another object of the present invention to provide a dental handpiece which has a source of illumination for illuminating the work area with a light beam which does not fluctuate in intensity, which does not risk being obscured by the dentist's hand or other parts of his body or by parts of the patient's body and which does not require a special connector.
It is a still further object of the present invention to provide a dental handpiece which is capable of illuminating the work area yet does not require a special drill apparatus and thus may be interchangeably used with drill apparati of conventional construction.
It is a concomitant object of the present invention to provide a dental handpiece which incorporates both a source of illumination and a built-in power source for such illumination so as to eliminate the need for fiber-optics.
One of the serious problems of positioning a power source at the interior of a dental handpiece is the presence there of the plurality of ducts for water and compressed air extending through the conventional handpiece and the necessity for maintaining nevertheless the size of the handpiece, particularly the outer peripheral size thereof, approximately the same as that of conventional handpieces which the dentist is used to handling. Thus, the relatively small diameter body portions of conventional handpieces have air and water passages extending longitudinally therethrough and occupying substantial portions of the cross-sectional space therein. It is therefore the principal object of the present invention to position a self-contained illuminating means in the dental handpiece without substantially increasing the outer peripheral size thereof and yet without interfering with the passage of gaseous and liquid fluids therethrough.